Nuclear Class #3 How does a nuclear power plant, or nuclear bomb make energy? How does the Sun make energy?

1. Nuclear Class #3 How does a nuclear power plant, or nuclear bomb make energy? How does the Sun make energy?

2. We have seen natural transmutation. That happens when radioactive material decays into some “more” stable material. Humans have discovered that we can cause decay, by blasting the nucleus of atoms with neutrons, causing them to become so unstable that they break apart, releasing crazy amounts of energy. A simple version of this is as follows: A neutron is slammed into the nucleus of a U-235 atom. This forms very unstable U-236. That literally splits apart into Kr and Ba, releasing some energy, and releasing 3 more neutrons. These three neutrons then blast three more U-235, starting over, releasing LOTS more energy.

3. U-235 + n° → Kr-90 + Ba-143 + 3n° + ENERGY A very small amount of mass is lost, smaller than the math here shows. It’s from the “strong force” and the mass of the nucleus “changing”. This BREAKS the Law of Conservation of Matter

4. Because it keeps growing, this is called a CHAIN REACTION. Fission is a chain reaction.

5. In a nuclear bomb, enough U-235 must be present to propel the reaction far enough, to release ENOUGH ENERGY to create a huge explosion. That amount is called the Critical Mass. If insufficient uranium is present, the reaction will release energy but not enough to destroy everything. In a power plant, there is NOT ENOUGH uranium to explode, but it can create LOTS of heat.

6. Fission creates heat, which is transferred into water that is very radioactive (red). Heat is transferred to the blue water, forming steam, which turns the TURBINE. That steam is condensed to water and pushed through the loop again. To condense that water, external cold water is pumped in from ocean/lake. Hot water is waste product. Electricity is produced by turning of the generator.

7. A different kind of nuclear reaction happens on the Sun, called FUSION. FUSION: whereby hydrogen atoms are squished into helium atoms, releasing crazy amounts of energy (really crazy amounts) On the Sun, simple Hydrogen, H-1 are crushed under the pressure and hot temperature at the core into helium. On Earth, scientists cannot do this, but have figured out a similar fusion reaction, similar, but not quite the same.

8. (simplified) FUSION on the SUN 4 H + 2 β– → He + energy (simplified) FUSION caused by SCIENTISTS H-2 + H-3 → He + n° + energy

9. In all fusion and fission reactions there is a small loss of mass. This is NOT normal in chemistry, but Einstein explained it with this famous equation:

10. Pros and Cons of Nuclear Energy Pros: long term cheap cost for electricity, no one ever killed on the job from radiation, small size of dangerous wastes, otherwise just hot water, jobs/economic boost, no green house gases/no global warming, no mistakes happened in the US ever, air conditioning when it’s hot, Cons: expensive building of plant, potential for meltdown, poisoning the Earth, hot water wastes, storage or disposal of wastes, large clean up costs for mistakes that might or have happened, an ALMOST mistake happened in 1979 at Three Mile Island Pennsylvania, some plants built upon earthquake zones which were unknown at the time they were built,